@mixin line($background) {
  content: ' ';
  position: absolute;
  left: 0;
  top: 0;
  width: 200%;
  border: 2upx solid $background;
  color: $background;
  height: 200%;
  transform-origin: left top;
  transform: scale(0.5);
}

@mixin line-top($background) {
  content: ' ';
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  height: 1px;
  border-top: 1px solid $background;
  color: $background;
  transform-origin: 0 0;
  transform: scaleY(0.5);
}
@mixin line-right($background) {
  content: ' ';
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  height: 1px;
  border-top: 1px solid $background;
  color: $background;
  transform-origin: 0 0;
  transform: scaleY(0.5);
}
@mixin line-bottom($background) {
  content: ' ';
  position: absolute;
  left: 0;
  bottom: 0;
  right: 0;
  height: 1px;
  border-bottom: 1px solid $background;
  color: $background;
  transform-origin: 0 0;
  transform: scaleY(0.5);
}
@mixin line-left($background) {
  content: ' ';
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  height: 1px;
  border-top: 1px solid $background;
  color: $background;
  transform-origin: 0 0;
  transform: scaleY(0.5);
}
